JP2024006855A - Separation and recovery method for laminate - Google Patents

Abstract

To provide: a separation and recovery method for a laminate suitable for plastic recycling, which realizes excellent detachment of a print layer and an adhesive layer even under conditions where the mass of the print layer being detached is large, and further inhibits reattachment of a detached print layer component; and a method for manufacturing a high-grade molding material obtained by hot-forming the recovered plastic base material.SOLUTION: A separation and recovery method for a laminate comprises a step of immersing a laminate including at least a plastic base material layer and a print layer in a detachment liquid so as to detach the print layer such that a print layer component detached from the plastic base material layer has a volume-based median diameter (D50) of at least 1 μm, and recovering a plastic base material. The mass of the print layer is 0.01 mass% or more based on the total mass of the detachment liquid.SELECTED DRAWING: None

Description

The present invention relates to a method for separating and recovering a laminate including at least a plastic base layer and a printed layer.

In recent years, packages, plastic bottles, and other plastic products made from plastic film are being discarded or dumped as garbage in the ocean, causing environmental pollution. These plastic products decompose in seawater and become submicron-sized fragments (microplastics) that float in the seawater. When these microplastics are ingested by marine organisms such as fish, they become concentrated inside the organisms, and there are concerns that they may affect the health of seabirds and humans who consume the marine organisms as food.

Examples of the above-mentioned plastic products include multi-layered food packaging packages using plastic films. In such food packaging packages, the film base material is polyester base material, nylon base material (NY), polypropylene base material ( Various plastic substrates are used, such as PP) and polyethylene substrates (PE). These film base materials are printed with printing ink, bonded to other film base materials or hot-melt resin base materials via an adhesive, etc., and then cut and heat-sealed to form a package. However, such multi-layered food packaging packages contain a mixture of a plurality of different types of materials that are not compatible with each other, so there is a problem that material recycling cannot be performed as is.

Regarding the material recycling of such multi-layered packaging materials, for example, Patent Documents 1 and 2 disclose that by treating a laminate including a release layer containing a polyurethane resin having a predetermined acid value with an alkaline aqueous solution, Techniques have been disclosed for removing printed layers not only from surface-printed laminates but also from multi-layered laminates.

Further, Patent Document 3 describes a technique in which a laminate having a polyester base material and a printed layer is immersed in an aqueous sodium hydroxide solution and stirred under certain conditions to detach the printed layer from the polyester base material. There is.

JP2020-090627A JP2021-098294A Special Publication No. 2022-510105

However, in the desorption steps described in Patent Documents 1 to 3, when the amount of the laminated body treated with the alkaline aqueous solution is increased in order to improve the treatment efficiency, the desorption performance decreases. In addition, since the amount of printed layer components in the treatment liquid increases, the printed layer becomes more likely to re-adhere to the substrate after detachment. Furthermore, if the stirring speed is increased in order to improve the releasability, a problem arises in that the desorbed printed layer becomes finely dispersed and becomes more likely to re-adhere to the plastic substrate. Here, "re-deposition" means that the detached layer such as the printed layer or adhesive layer that has detached from the base material is finely dispersed by stirring and re-attaches to the base material. This can cause coloration and deterioration of the properties of recycled materials. That is, the molding material obtained by recycling the base material to which the printed layer has been redeposited as described above causes deterioration in appearance and physical properties due to coloring.

Therefore, the object of the present invention is to achieve excellent removability of the printed layer and adhesive layer even under conditions where the amount of the printed layer is large during the desorption process, and to suppress redeposition of the removed printed layer components. The object of the present invention is to provide a method for separating and collecting laminates suitable for plastic recycling. Another object of the present invention is to provide a method for producing a high-quality molding material obtained by heat-molding a recovered plastic base material.

That is, in the present invention, a laminate including at least a plastic base material layer and a printed layer is immersed in a desorption liquid and stirred or shaken, and the printed layer is divided into volumes based on the printed layer components desorbed from the plastic base layer. A method for separating and recovering a laminate, the method comprising the step of recovering a plastic base material by desorbing the plastic base material so that the median diameter (D50) of the plastic base material is 1 μm or more,
The present invention relates to a method for separating and recovering a laminate, wherein the content of the printed layer is 0.01% by mass or more based on the total mass of the desorption liquid.

The present invention also relates to a method for separating and recovering the above-mentioned laminate, in which the span value A of the detached printed layer component expressed by the following formula is 10 or less.
A=(D90-D10)/D50
D10: Cumulative 10% diameter of the volume-based particle size distribution obtained by laser diffraction particle size distribution measurement of the detached printed layer components D90: Cumulative 10% diameter of the volume-based particle size distribution obtained by laser diffraction particle size distribution measurement of the detached printed layer components Cumulative 90% diameter

The present invention also relates to a method for separating and recovering the above-mentioned laminate, in which the plastic base layer is a polyolefin base material.

Further, the present invention provides separation of the above-mentioned laminate, wherein the desorption liquid contains water and a surfactant, and the content of the surfactant is 0.001% by mass or more in the total mass of the desorption liquid. Regarding the collection method.

Further, the present invention provides the above laminated layer, wherein the printing layer includes a colorant, a binder resin, and a dispersant, and the content of the dispersant is 0.01% by mass or more with respect to the total mass of the colorant. This article relates to a method for separating and recovering a body.

The present invention also relates to a method for separating and recovering the above-mentioned laminate, in which the dispersant includes a pigment derivative and/or a resin-type dispersant.

The present invention also relates to a method for separating and recovering the above-mentioned laminate, wherein the dispersant contains a pigment derivative, and the content of the pigment derivative is 0.01 to 10% by mass based on the total mass of the colorant.

The present invention also relates to a method for separating and recovering the laminate described above, wherein the content of the laminate is 1.5% by mass or more based on the total mass of the desorbed liquid.

The present invention also relates to a method for separating and recovering the laminate described above, which includes a step in which the desorption liquid is a basic aqueous solution, and a step of desorbing the printed layer in the basic aqueous solution and recovering the plastic substrate.

The present invention also relates to a method for producing a molding material, which comprises melting and kneading the plastic base material recovered by the above method for separating and recovering a laminate.

The present invention also relates to a method for producing a molded body, characterized in that a molding material obtained by the above-mentioned production method is heat-molded.

The present invention provides excellent removability of the printed layer and adhesive layer even under conditions where the amount of the printed layer is large during the desorption process, and furthermore, the re-adhesion of the removed printed layer components is suppressed for plastic recycling. It is possible to provide a method for separating and recovering a laminate suitable for. Furthermore, it is possible to provide a method for producing a high-quality molding material obtained by heat-molding the recovered plastic base material.

The embodiments of the present invention will be described in detail below, but the embodiments or description of requirements described below are examples of the embodiments of the present invention, and the present invention does not exceed the gist thereof. Not limited.

The method for separating and recovering a laminate of the present invention includes immersing a laminate including at least a plastic base layer and a printed layer in a desorption liquid, and removing the volume of the printed layer components that have been desorbed from the plastic base layer. The printing layer comprises a step of desorbing and recovering the plastic base material so that the median diameter (D50) in the standard is 1 μm or more, and the printed layer is 0.01% by mass or more based on the total mass of the desorbing liquid. characterized by something.

In the separation and recovery of laminates, if the amount of laminate relative to the desorbing liquid is increased in order to improve processing efficiency, the amount of printed layer relative to the desorbing liquid also increases, which worsens the releasability and further increases the rate of desorption. The subsequent printed layer components are more likely to re-adhere to the substrate after being detached. Furthermore, under stirring conditions, the frequency of collisions of the laminate increases, so the printed layer components tend to become smaller after detachment.

The inventors have found that by desorbing the printed layer components such that the median diameter (D50) of the components of the printed layer after desorption is 1 μm or more under conditions where the amount of the printed layer is large relative to the desorbing liquid, the printed layer can be improved. It has been found that reattachment can be effectively suppressed while maintaining detachability. This is considered to be due to the fact that the mobility of the printing layer components in the desorption solution after desorption and the polarity of the surface are appropriately controlled.

In order to desorb so that the median diameter of the printing layer component of the desorption layer becomes 1 μm or more, the conditions during the desorption test such as stirring speed are selected, and the desorption liquid contains a surfactant. Examples include, but are not limited to, means such as incorporating a dispersant into the printing layer, and it is preferable to appropriately combine each means. Details of each means will be described later.

<Separation and recovery method>
The method for separating and recovering a laminate of the present invention includes immersing a laminate including at least a plastic base layer and a printed layer in a desorption liquid, and removing the volume of the printed layer components that have been desorbed from the plastic base layer. It includes a step of removing the plastic base material so that the median diameter (D50) in the standard is 1 μm or more and recovering the plastic base material.
In the present invention, "detachment" refers to the detachment of the base material from the laminate as the detachment layer dissolves or swells with a detachment liquid and peels off. (2) cases in which the base material detaches, and (2) cases in which the detachment layer peels off due to neutralization, swelling, etc., even if the detachment layer does not dissolve, and the base material detaches.

Since the purpose of the present invention is to obtain a plastic base material after desorption as a recycled base material or recycled base material, it is preferable to remove as much of the desorption layer and the like as possible from the plastic base material. Specifically, it is preferable that at least 50% by mass or more of 100% by mass of the desorption layer is desorbed in the area and film thickness direction. More preferably, 60% by mass or more, still more preferably 80% by mass or more, particularly preferably 90% by mass or more is desorbed.

<Particle size distribution of detached printing layer components>
In the present invention, the volume-based median diameter (D50) and span value A of the printed layer component detached from the plastic base layer are measured using a laser diffraction particle size distribution measuring device. The span value A is expressed by the following formula.
A=(D90-D10)/D50
D10: Cumulative 10% diameter of the volume-based particle size distribution obtained by laser diffraction particle size distribution measurement of the detached printed layer components D90: Cumulative 10% diameter of the volume-based particle size distribution obtained by laser diffraction particle size distribution measurement of the detached printed layer components Cumulative 90% diameter

In the present invention, it is important that the median diameter of the detached printing layer components is 1 μm or more. When the median diameter of the detached printing layer component is 1 μm or more, it is possible to suppress the detached printing layer component from re-adhering to the substrate as described above, and to obtain a high-performance recycled material. The median diameter of the detached printing layer component is preferably 5 μm or more, more preferably 10 μm or more, even more preferably 15 μm or more, particularly preferably 20 μm or more. Further, the median diameter of the detached printing layer component is preferably 1000 μm or less, more preferably 800 μm or less. It is preferable that the median diameter is 1000 μm or less because it facilitates separation of the base material and printing layer components after desorption.

The span value A represents the particle size distribution width of the detached printed layer components, and the larger the value, the wider the particle size distribution width, which tends to include fine printed layer components that are likely to re-adhere to the substrate.
The span value A is preferably 10 or less, more preferably 8 or less, and even more preferably 5 or less. It is preferable that the span value is 10 or less because re-adhesion of the detached printed layer can be suppressed.

<Desorption liquid>
The desorption liquid may be one that swells and dissolves the desorption layer, and can be appropriately selected in consideration of ease of desorption of the desorption layer, which will be described later. Examples of such a desorption liquid include water, a basic aqueous solution, and an acidic aqueous solution. These desorption liquids may be heated.
The release liquid is more preferably a basic aqueous solution containing a basic compound from the viewpoint of removing a urethane adhesive layer commonly used in packaging materials.

[Surfactant]
It is preferable that the desorption liquid contains water and a surfactant. The surfactant mainly plays a role in improving the releasability of the release layer. This is thought to be because the action of the surfactant makes it easier for the release liquid to permeate into release layers such as the primer layer, printing layer, and adhesive layer, promoting release properties. Further, the median diameter of the printing layer components desorbed in the desorption liquid can be easily controlled to 1 μm or more. In addition, when the amount of the laminate relative to the desorbing liquid is increased during separation and recovery, the laminate and the separated base material tend to curl while enveloping the desorbed ink pieces. However, it is difficult to cleanly remove ink particles etc. caught in the curls. However, since the desorption liquid contains a surfactant, the surfactant is adsorbed onto the surface of the laminate and the separated base material, thereby suppressing curling. As a result, detachability is improved and re-adhesion can be suppressed.
Furthermore, when the desorption liquid contains a surfactant, it is possible to desorb the printed layer in contact with the plastic substrate even without a desorption layer.

The HLB value is an index value related to the affinity of surfactants for water and oil, and is divided into equal parts, with the HLB value of substances without hydrophilic groups being 0 and the HLB value of substances having only hydrophilic groups being 20. be. The concept of HLB was proposed by William Griffin of the Atlas Powder Company in 1949, and several methods for determining it by calculation have been proposed. In the present invention, the HLB value can be determined from the following equation using the Griffin method.
Formula) HLB=20×[(molecular weight of hydrophilic group contained in surfactant)/(molecular weight of surfactant)]
Examples of the hydrophilic group contained in the surfactant include a hydroxyl group and an ethyleneoxy group.

The HLB value of the surfactant in the present invention is preferably 7 or more. When the HLB is 7 or more, excellent deinking properties and reattachment properties are exhibited. The HLB value of the surfactant is preferably 8 or more, more preferably 10 or more. Further, the HLB value of the surfactant is preferably 20 or less, more preferably 19 or less, and still more preferably 17 or less. It is preferable that the HLB value is 20 or less because it has excellent antifoaming properties.

Types of surfactants include, for example, nonionic, anionic, cationic, and amphoteric surfactants, and suitable types and amounts can be selected and used depending on the required properties. From the viewpoint of detachability and foamability, at least one kind selected from the group consisting of anionic surfactants and nonionic surfactants is preferable.
Further, the surfactant preferably has a structure in which alkylene oxide (hereinafter also referred to as AO) is added because deinking properties and reattachment properties are improved.

(Nonionic surfactant)
The nonionic surfactant is not particularly limited, but is preferably an alkylene oxide adduct to which alkylene oxide is added. More preferred are compounds obtained by adding alkylene oxide to alcohols having active hydrogen, compounds obtained by adding alkylene oxide to amines, or compounds obtained by adding alkylene oxide to fatty acids. The above addition may be either random addition or block addition. Further, the alkylene oxide preferably has 2 to 4 carbon atoms.
More preferred nonionic surfactants are alcohol-based nonionic surfactants obtained by adding an alkylene oxide having 2 to 4 carbon atoms to an alcohol.

[Alcohol-based nonionic surfactant]
Examples of alcohol-based nonionic surfactants include alkylene oxide adducts of primary or secondary alcohols having a total of 8 to 24 carbon atoms, or alkylene oxide adducts of alkylphenols having a total of 8 to 12 carbon atoms. It will be done. The above primary or secondary alcohol having a total of 8 to 24 carbon atoms may be either saturated or unsaturated.
Examples of the primary or secondary alcohol having a total of 8 to 24 carbon atoms include lauryl alcohol, stearyl alcohol, oleyl alcohol, dodecyl alcohol, arachidyl alcohol, behenyl alcohol, lignoceryl alcohol, myristyl alcohol, and the like.
Furthermore, examples of the alkylene oxide added to the alcohol include ethylene oxide, propylene oxide, and butylene oxide, and it is preferable that ethylene oxide is essential. The number of moles of alkylene oxide added is preferably 1 to 100 moles, more preferably 2 to 50 moles, per mole of alcohol or alkylphenol. It is preferable that the content is within the above range because it has particularly excellent releasability.

[Fatty acid-based nonionic surfactant]
The structure of the fatty acid-based nonionic surfactant is not particularly limited, but examples include alkylene oxide adducts of higher fatty acids having a total of 10 to 24 carbon atoms, and saturated or unsaturated surfactants having a total of 10 to 24 carbon atoms. Examples include fats and oils made of esters of higher fatty acids and glycerin, and alkylene oxide adducts of mixtures of the above-mentioned fats and oils and 2 to 10 polyhydric alcohols. The above-mentioned higher fatty acids having a total of 10 to 24 carbon atoms may be either saturated or unsaturated.
Examples of the higher fatty acids having a total of 10 to 24 carbon atoms include saturated higher fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, and behenic acid; palmitoleic acid, oleic acid, elaidic acid, linoleic acid, Examples include unsaturated higher fatty acids such as linolenic acid, erucic acid, and ricinoleic acid. Examples of the di- to decavalent polyhydric alcohol include ethylene glycol, propylene glycol, glycerin, polyglycerin, sorbitol, sorbitan, and sucrose. The type of alkylene oxide and the number of moles added are the same as those described in the [Alcoholic nonionic surfactant] section above.

[Amine-based nonionic surfactant]
Examples of the amine-based nonionic surfactant include AO adducts of saturated or unsaturated primary or secondary amines having a total of 8 to 36 carbon atoms. Examples of amines include 2-ethylhexylamine, di2-ethylhexylamine, laurylamine, dilaurylamine, tetradecylamine, ditetradecylamine, hexadecylamine, dihexadecylamine, stearylamine, distearylamine, oleylamine, di- Examples include oleylamine. Further, the type of AO and the number of moles added are the same as above.

(Anionic surfactant)
The anionic surfactant is preferably a non-soap type, such as a sulfonic acid-based anionic surfactant, a sulfate-based anionic surfactant, a carboxylic acid-based anionic surfactant, or a phosphate-based anionic surfactant. Examples include activators.

[Sulfonic acid-based anionic surfactant]
Examples of the sulfonic acid-based anionic surfactants include alkylsulfonic acids, alkylbenzenesulfonic acids, alkylnaphthalenesulfonic acids, alkyldiphenyl ether disulfonic acids, alkylmethyltaurine, sulfosuccinic acid diesters, alkylene oxide adducts of sulfonic acids, and these. Examples include salt. Specific examples include hexane sulfonic acid, octanesulfonic acid, decane sulfonic acid, dodecane sulfonic acid, toluene sulfonic acid, cumene sulfonic acid, octylbenzenesulfonic acid, dodecylbenzenesulfonic acid, dinitrobenzenesulfonic acid, and lauryl dodecyl phenyl ether disulfone. An acid etc. can be used.

[Sulfate ester anionic surfactant]
Examples of the sulfate-based anionic surfactant include sulfuric esters (alkyl ether sulfuric esters), alkylene oxide adducts of sulfuric esters, and salts thereof. Specific examples include lauryl sulfate, myristyl sulfate, and polyoxyethylene lauryl ether sulfate.

[Carboxylic acid-based anionic surfactant]
Examples of the carboxylic acid-based anionic surfactant include alkyl carboxylic acids, alkylbenzene carboxylic acids, alkylene oxide adducts of carboxylic acids, and salts thereof. Specific examples include lauric acid, myristic acid, palmitic acid, stearic acid, polyoxyethylene lauryl ether acetic acid, and polyoxyethylene tridecyl ether acetic acid.

[Phosphate ester-based anionic surfactant]
Examples of the phosphoric ester-based anionic surfactant include phosphoric esters (alkyl ether phosphates), alkylene oxide adducts of phosphoric esters, and salts thereof. Specific examples include octyl phosphate, lauryl phosphate, tridecyl phosphate, myristyl phosphate, cetyl phosphate,
Stearyl phosphate, polyoxyethylene octyl ether phosphate, polyoxyethylene lauryl ether phosphate, etc. can be used.

The anionic surfactant preferably has an alkyl group having 2 to 24 carbon atoms or an alkenyl group having 2 to 24 carbon atoms, and more preferably has an alkyl group having 8 to 18 carbon atoms. The alkyl group or alkenyl group may be linear or branched.
Further, when the anionic surfactant is an alkylene oxide adduct, examples of the alkylene oxide include ethylene oxide, propylene oxide, and butylene oxide, with ethylene oxide being preferred. The number of moles of alkylene oxide added is preferably 1 to 12 moles, more preferably 1 to 8 moles, per mole of alcohol or alkylphenol. It is preferable that the content is within the above range because it has particularly excellent releasability.

Examples of the salt constituting the above-mentioned anionic surfactant include metal salts such as sodium, potassium, magnesium, and calcium. These salts may be used alone or in combination of two or more.
Among them, preferred anionic surfactants are sulfonate type and phosphate type from the viewpoint of detachability and reattachment property, and more preferred are alkyl sulfonates and polyoxyalkylene alkyl ether sulfonates. , polyoxyalkylene alkyl ether phosphate, and the like.

(Cationic surfactant)
Examples of the cationic surfactant include alkylamine salts and quaternary ammonium salts. Specifically, stearylamine acetate, trimethylyacyanmonium chloride, trimethyltallow ammonium chloride, dimethyldioleylammonium chloride, methyloleyldiethanol chloride, tetramethylammonium chloride, laurylpyridinium chloride, laurylpyridinium bromide, laurylpyridinium disulfate, cetylpyridinium bromide. , 4-alkylmercaptopyridine, poly(vinylpyridine)-dodecyl bromide, dodecylbenzyltriethylammonium chloride, and the like can be used.

(Ampholytic surfactant)
Examples of amphoteric surfactants include lauryldimethylaminoacetic acid betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, coconut oil fatty acid amidopropyldimethylaminoacetic acid betaine, polyoctylpolyaminoethylglycine, and imidazoline. Examples include derivatives.

These surfactants may be used alone or in combination of two or more. The content of the surfactant in the desorption solution is preferably in the range of 0.001 to 10% by mass, more preferably in the range of 0.005 to 7% by mass, based on the mass of the desorption solution. , more preferably 0.03 to 5% by weight, still more preferably 0.05 to 3% by weight. If it is 0.001% by mass or more, it is preferable because it has excellent deinking properties and it is easy to control the median diameter of the detached printed layer component to 1 μm or more, and if it is 10% by mass or less, it is preferable from the viewpoint of antifoaming properties.

[Defoaming agent]
In the present invention, it is also preferable that the desorption liquid further contains an antifoaming agent. By using an antifoaming agent in combination with the above-mentioned surfactant, it is possible to exhibit good antifoaming properties without reducing detachability and reattachment properties, and to suppress foaming caused by the surfactant. Examples of antifoaming agents include silicone compounds and non-silicone compounds.

(Silicone compound)
Examples of the silicone compound include emulsion type, self-emulsifying type, oil type, oil compound type, and solvent type.
Emulsion type is a silicone antifoaming agent that emulsifies a silicone oil compound with an activator to form an O/W type emulsion.For example, "KM-89" and "KM-98" manufactured by Shin-Etsu Chemical, Examples include "FC2913" and "SILFOAMSE47" manufactured by Wacker Silicone, and "BYK-015" and "BYK-1640" manufactured by BYK Chemie Japan.
Self-emulsifying type antifoaming agents are silicone antifoaming agents with 100% active ingredients that become an emulsion when diluted with water and mixed.For example, "KS-540" and "X-50-1176" manufactured by Shin-Etsu Chemical Co., Ltd. , "SILFOAM SD670" and "SILFOAM SD850" manufactured by Asahi Kasei Wacker Silicone.
The oil type is a 100% silicone oil antifoaming agent that does not contain solvents or additives. AK12500'' and BYK-1770 manufactured by BYK Chemie Japan.
The oil compound type is a silicone antifoaming agent made by blending silica particles with silicone oil, such as "KM-89" and "KM-98" manufactured by Shin-Etsu Chemical, "SILFOAM SC370" manufactured by Asahi Kasei Wacker Silicone, Examples include "PULPSIL22274VP" and "BYK-017" and "BYK-018" manufactured by BYK Chemie Japan.
Solvent type is a silicone antifoaming agent made by dissolving silicone oil in a solvent, such as "KM-89" and "KM-98" manufactured by Shin-Etsu Chemical, "BYK-019" manufactured by BYK Chemie Japan, "BYK-025" is an example.

(Non-silicone compound)
Examples of the non-silicone compounds include fatty acid ester compounds, urea resin compounds, paraffin compounds, polyoxyalkylene glycol compounds, acrylic ester copolymers, ester polymers, ether polymers, and amide polymers. Examples include emulsified types of mineral oil, polysiloxane adducts, fluorine compounds, vinyl polymers, acetylene alcohol, acrylic polymers, special vinyl polymers, ethylene glycol, and higher alcohols (octyl alcohol, cyclohexanol, etc.).

The antifoaming agents may be used alone or in combination of two or more. The content of the antifoaming agent in the desorption liquid is preferably in the range of 0.0001 to 5% by mass, more preferably in the range of 0.001 to 4.5% by mass, based on the mass of the desorption liquid. It is more preferably 0.01 to 4% by weight, still more preferably 0.02 to 3.5% by weight, particularly preferably 0.03 to 3% by weight. When it is 0.0001% by mass or more, the antifoaming property is excellent, and when it is 5% by mass or less, the deinking property and reattachment property are excellent.

The above antifoaming agents have good alkali resistance and are difficult to reduce deinking properties and redeposition properties when combined with the above surfactants, so emulsion type silicone compounds and self-emulsifying silicone compounds are used. , and a non-silicone compound.

[Basic compound]
As described above, the desorption liquid used in the present invention is preferably a basic aqueous solution containing a basic compound from the viewpoint of desorption of the urethane adhesive layer commonly used in packaging materials.
The basic compound is not particularly limited, and examples include sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH) ₂ ), ammonia, barium hydroxide (Ba(OH) ₂ ), Sodium carbonate (Na ₂ CO ₃ ) is preferably used. More preferably, it is at least one selected from the group consisting of sodium hydroxide and potassium hydroxide.
The content of the basic compound in the basic aqueous solution is preferably 0.5 to 20% by mass, more preferably 1 to 15% by mass, even more preferably 3 to 15% by mass, based on the mass of the basic aqueous solution. range. Within the above range, the basic aqueous solution can maintain sufficient basicity to recover the plastic substrate by dissolving or swelling the release layer described below.

The desorption liquid permeates through the end portion of the laminate, contacts the desorption layer, and dissolves or swells, thereby separating the plastic base material and the desorption layer. Therefore, in order to proceed with the desorption process efficiently, it is preferable that the laminate is cut or crushed and the desorption layer is exposed in the cross section when it is immersed in the desorption liquid. In such a case, the base material layer can be detached in a shorter time.

When the laminate is separated in the desorption solution, the laminate preferably contains 0.1% by mass or more and 10% by mass or less, more preferably 1% by mass or more and 8% by mass or less, based on the total mass of the desorption solution. , more preferably 1.5% by mass or more and 7% by mass or less, still more preferably 2% by mass or more and 6% by mass or less. A content of 0.1% by mass or more is preferable from the viewpoint of processing efficiency. A content of 10% by mass or less is preferable from the viewpoint of removability.

The printed layer when separating the laminate in the desorption solution is 0.01% by mass or more, preferably 0.05% by mass or more and 1% by mass or less, more preferably 0.05% by mass or more and 1% by mass or less, based on the total mass of the desorption solution. is 0.1% by mass or more and 0.5% by mass or less. A content of 0.01% by mass or more is preferable from the viewpoint of processing efficiency. A content of 1% by mass or less is preferable from the viewpoint of reattachment properties.

The temperature of the desorption liquid during immersion of the laminate is preferably in the range of 25 to 120°C, more preferably 30 to 120°C, particularly preferably 30 to 80°C. The immersion time in the desorption solution is preferably in the range of 1 minute to 24 hours, more preferably 1 minute to 12 hours, still more preferably 1 minute to 6 hours. In order to improve the desorption efficiency, it is preferable to stir or shake the desorption liquid, circulate it, etc. The rotation speed is preferably 80 to 5000 rpm, more preferably 80 to 4000 rpm.

After the release layer is detached from the laminate and the plastic base material is recovered, a recycled base material can be obtained through a process of washing and drying the obtained plastic base material. The removal rate of the release layer on the surface of the substrate is preferably 70% or more, more preferably 80% or more, particularly preferably 90% or more, based on the area of the release layer before desorption.
Further, the obtained recycled base material can be processed into pellets using an extruder or the like and reused as recycled resin.

<Laminated body>
The laminate used in the present invention includes at least a plastic base layer and a printed layer. The layer in contact with the plastic base material is desorbed by the above-mentioned desorption liquid, making it possible to collect and recycle the plastic base material. In the present invention, in order to improve releasability, it is preferable to provide a release layer in contact with the plastic base layer.

<Print layer>
In the present invention, the printing layer is an essential component, and may be provided in contact with the plastic substrate, or in the case where the laminate has a primer layer, it may be provided in contact with the primer layer. The printed layer is a layer that forms an arbitrary printed pattern for the purpose of decoration, giving a sense of beauty, indicating contents, expiration date, manufacturer or seller, etc., and includes a solid printed layer. The printing layer may be formed of a single layer or a plurality of layers.
When the printing layer contains a water-soluble resin or a compound having an acidic group, which will be described later, it also functions as a release layer.
The printing ink used to form the printing layer can be manufactured by dissolving and/or dispersing at least a colorant, a dispersant, and a binder resin in a solvent, and may contain other components as necessary. You can.

[Colorant]
The printing layer may be colored or colorless and contains known colorants used in printing inks and paints. Such coloring agents are not particularly limited, and in addition to inorganic pigments, organic pigments, and dyes, metal powders that provide metallic luster, near-infrared absorbing materials, and ultraviolet absorbing materials may be used.
Examples of inorganic pigments include colored pigments such as titanium oxide, red iron oxide, navy blue, ultramarine blue, carbon black, and graphite; extender pigments such as calcium carbonate, kaolin, clay, barium sulfate, aluminum hydroxide, and talc.
As the organic pigment, soluble azo pigments, insoluble azo pigments, azo lake pigments, condensed azo pigments, copper phthalocyanine pigments, condensed polycyclic pigments, etc. are preferably used.
Note that the pigments are not limited to these, and those described by the generic names of Color Index can be used as appropriate. Among these, when the desorbing liquid is a basic aqueous solution, a pigment that does not dissolve in the basic aqueous solution and has alkali resistance is preferable. By preventing pigment elution, the base aqueous solution can be easily reused.
The alkali resistance of a pigment is generally estimated based on the skeleton or structure of the pigment, and examples of pigments with alkali resistance include inorganic pigments, C.I. I. Pigment Blue 15, C. I. Pigment Yellow 83 is mentioned.
When the pigment is titanium oxide, the content of titanium oxide in the printing layer is preferably 20 to 80% by weight, more preferably 30 to 75% by weight. Further, when the pigment is an inorganic pigment other than titanium oxide, an extender pigment, or an organic pigment, the content of each of these pigments in the printing layer is preferably 0.5 to 60% by mass, more preferably 10 to 50% by mass. Mass%.

[Dispersant]
When the print layer contains a pigment derivative and/or a resin-type dispersant as a colorant dispersant, the releasability is improved. Moreover, the median diameter of the printing layer components desorbed in the desorption liquid can be easily controlled to 1 μm or more. Furthermore, the dispersion stability and stability over time of the ink are improved. Although these may be used alone, it is preferable to use them together because the dispersion stability and stability over time will be further improved.

(pigment derivative)
Pigment derivatives are compounds in which substituents have been introduced into the pigment skeleton. In the printing ink, the pigment skeleton of the pigment derivative is adsorbed to the surface of the pigment in the printing ink, and the substituent part of the pigment derivative is oriented to the solvent in the printing ink, which has the effect of dispersing the pigment in the printing ink. have
Examples of pigment derivatives include those in which functional groups such as carboxyl groups, sulfonic acid groups, carbonyl groups, and sulfonyl groups are added to the skeleton of pigments such as phthalocyanine, azo, anthraquinone, and quinacridone, and salts thereof. can be preferably used. These can be used alone or in combination.

As commercially available pigment derivatives, Solsperse 5000, Solsperse 12000 (manufactured by Japan Lubrizol), BYK-SYNERGIST 2100, BYK-SYNERGIST 2105 (manufactured by Big Chemie Japan), Efka 6745, Efka 6750 (manufactured by BASF), etc. are preferably used. can do. These can be used alone or in combination.

Preferably, the pigment derivative exhibits the same or similar color as the pigment in the ink. For example, when added to black ink or cyan ink, phthalocyanine pigment derivatives can be preferably used as the pigment derivatives.

The total amount of pigment derivatives is preferably 0.01 to 10% by weight, more preferably 0.05 to 6% by weight, and preferably 0.1 to 4% by weight based on the entire colorant. More preferred. When the amount is 0.01% by mass or more, the dispersion stability of the printing ink will be good and the releasability will also be improved. Furthermore, by setting the content to 0.01 to 10% by mass, the median diameter of the detached printed layer component can be easily controlled to 1 μm or more, and it can be recycled into a high-quality recycled molding material.

(Resin type dispersant)
The resin-type dispersant has an affinity site for the pigment composition that has the property of adsorbing to the pigment composition, and a site that is compatible with the pigment composition carrier. It functions to stabilize the dispersion in the carrier. Specifically, resin-type dispersants include polycarboxylic acid esters such as polyurethane and polyacrylate, unsaturated polyamides, polycarboxylic acids, polycarboxylic acid (partial) amine salts, polycarboxylic acid ammonium salts, and polycarboxylic acid alkylamine salts. , polysiloxanes, long-chain polyaminoamide phosphates, hydroxyl group-containing polycarboxylic acid esters, modified products thereof, amides formed by the reaction of poly(lower alkylene imine) with polyesters having free carboxyl groups, and their salts. Water-soluble oil-based dispersants such as (meth)acrylic acid-styrene copolymer, (meth)acrylic acid-(meth)acrylic acid ester copolymer, styrene-maleic acid copolymer, polyvinyl alcohol, polyvinylpyrrolidone, etc. Resins, water-soluble polymer compounds, polyesters, modified polyacrylates, ethylene oxide/propylene oxide adducts, phosphoric esters, etc. are used, and these can be used alone or in combination of two or more, but It is not necessarily limited to these.

The total amount of the resin type dispersant is preferably 0.01 to 30% by mass, more preferably 0.05 to 20% by mass, and 0.1 to 10% by mass based on the entire colorant. It is even more preferable. When the amount is 0.01% by mass or more, the dispersion stability of the printing ink will be good and the releasability will also be improved. Furthermore, the median diameter of the printing layer components desorbed in the desorption liquid can be easily controlled to 1 μm or more. Further, if the content is 30% by mass or less, the water resistance of the printed layer will be good.

[Binder resin]
Examples of the binder resin for the printing layer include nitrocellulose, cellulose acetate/propionate and other fiber materials, chlorinated polypropylene, vinyl chloride-vinyl acetate copolymer, polyester, acrylic, urethane resin, and acrylic urethane. , polyamide-based, polybutyral-based, cyclized rubber-based, chlorinated rubber-based, or a combination of these as appropriate can be used. When containing a water-soluble resin or a compound having an acidic group, which will be described later, the printing layer also functions as a release layer. These resins may be used alone or in combination of two or more.

[Primer layer]
The laminate used in the present invention may have a primer layer. When the laminate has a primer layer, the primer layer is disposed in contact with the plastic base material, contains a water-soluble resin or a compound having an acidic group, and is capable of being removed from the plastic base material by dissolving or peeling with a desorbing liquid. It is preferable to play the role of separating.

(Water-soluble resin)
The water-soluble resin may be any resin that can swell or dissolve in water and be detached from the plastic base material. The water may be heated to a temperature of about 25 to 100°C. Thereby, the primer layer can be removed with water (including hot water).
Such resins can be selected from known resins as long as they do not impair water solubility, such as water-soluble polyester resins, water-soluble polyamide resins, water-soluble polyimide resins, water-soluble acrylic resins, water-soluble polyurethane resins, and water-soluble polyurethane resins. Examples include water-soluble polyallylamine resin, water-soluble phenol resin, water-soluble epoxy resin, water-soluble phenoxy resin, water-soluble urea resin, water-soluble melamine resin, polyvinyl alcohol resin, and modified products of these resins. These can be used alone or in combination of two or more. Among them, polyvinyl alcohol (PVA) resin is preferably used from the viewpoint of easy availability and removability.
When the water-soluble resin has film-forming properties, the water-soluble resin may be used as the binder resin constituting the primer layer.

In addition to unmodified polyvinyl alcohol, polyvinyl alcohol resins include modified polyvinyl alcohol obtained by copolymerizing various monomers during the production of vinyl ester resins and saponifying this, and various types of polyvinyl alcohol obtained by post-modification of unmodified polyvinyl alcohol. Various post-modified polyvinyl alcohols into which functional groups have been introduced may also be used. Further, modified polyvinyl alcohol may be further modified after modification. These modifications can be carried out within a range that does not impair the water solubility of the polyvinyl alcohol resin.
These resins may be used alone or in combination of two or more.

Preferred examples of the polyvinyl alcohol resin include resins containing a structural unit having a primary hydroxyl group in the side chain, and ethylene-modified polyvinyl alcohol resins. Among these, polyvinyl alcohol resins containing a structural unit having a primary hydroxyl group in the side chain are preferred because they have excellent melt moldability and water solubility. The number of primary hydroxyl groups in these structural units is usually 1 to 5, preferably 1 to 2, and more preferably 1. Moreover, it is preferable to have a secondary hydroxyl group in addition to the primary hydroxyl group.

The saponification degree (measured according to JIS K 6726) of the polyvinyl alcohol resin used in the present invention is usually 60 to 100 mol%. Further, the preferable range of the degree of saponification varies depending on the modified species; for example, in the case of unmodified polyvinyl alcohol resin, it is usually 60 to 99.9 mol%, preferably 70 to 99.0 mol%, more preferably 75 to 98 mol%. .5%. The degree of saponification of the modified polyvinyl alcohol resin containing a side chain 1,2-diol structural unit is usually 60 to 99.9 mol%, preferably 65 to 99.8 mol%, more preferably 70 to 99.5 mol%. be. If the degree of saponification is too low, water solubility tends to decrease. The degree of saponification of the ethylene-modified polyvinyl alcohol resin modified with a small amount of ethylene is usually 60 mol% or more, preferably 70 to 99.5 mol%, particularly preferably 75 to 99.0 mol%.
It is preferable that the degree of saponification is within the above range because it provides excellent water solubility and good desorption properties. It is also preferred because it has excellent coating properties when forming a primer layer.

The average degree of polymerization of the polyvinyl alcohol resin (measured according to JIS K 6726) is usually 100 to 3,000, preferably 150 to 2,000, more preferably 180 to 1,000, particularly preferably 200 to 800.

(Compound with acidic group)
As the compound having an acidic group, a resin having an acidic group or a low molecular weight compound having an acidic group may be used. Thereby, the primer layer can be removed with the above-mentioned basic aqueous solution.

Examples of the resin having an acidic group include cellulose resin, urethane resin, polyamide resin, vinyl chloride/vinyl acetate copolymer, ketone resin, polyester resin, and (meth)acrylic resin. Examples of the acidic group include a carboxy group, a phosphoric acid group, a sulfo group, a sulfino group, and esters or salts thereof.
Further, as the resin having an acidic group, a rosin modified resin having an acid value such as a maleated rosin or a fumarated rosin can be used.
In addition, as resins having acidic groups, polymerizable monomers having a carboxy group such as itaconic acid, maleic acid, fumaric acid, and cinnamic acid; polymerizable monomers that are acid anhydrides such as itaconic anhydride and maleic anhydride; sulfone Styrene-(meth)acrylic copolymerized with a polymerizable monomer having an acidic group such as a polymerizable monomer having a sulfonic acid group such as styrene; a polymerizable monomer having a sulfonamide group such as vinylbenzenesulfonamide; A radical copolymer such as a resin, a styrene-(anhydrous) maleic acid resin, a terpene-(anhydrous) maleic acid resin, or an acid-modified polyolefin resin can be used.
These may be used alone or in combination of two or more.

A low molecular weight compound having an acidic group refers to a compound having no molecular weight distribution and having a molecular weight of 1,000 or less. Examples of such compounds include saturated fatty acids such as lauric acid, myristic acid, palmitic acid, margaric acid, and stearic acid; oleic acid, linoleic acid, linolenic acid, arachidonic acid, eicosapentaenoic acid, docosahexaenoic acid, sorbic acid, etc. unsaturated fatty acids; hydroxy acids such as lactic acid, malic acid, and citric acid; aromatic carboxylic acids such as benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, salicylic acid, gallic acid, mellitic acid, and cinnamic acid; oxalic acid, Dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, fumaric acid, and maleic acid; Tricarboxylic acids such as aconitic acid; Oxocarboxylic acids such as pyruvic acid and oxaloacetic acid; Carboxylic acid derivatives such as amino acids and nitrocarboxylic acids ; Examples include acid anhydrides such as trimellitic anhydride and pyromellitic anhydride.
A low molecular weight compound having an acidic group can form a primer layer by using it in combination with the above-mentioned resin having an acidic group or a known binder resin constituting a known primer layer.

The primer layer preferably contains a compound having an acidic group from the viewpoint of suitability for recoating. Further, from the viewpoint of printability, it is preferable to include a urethane resin having an acidic group, an acrylic resin having an acidic group, and a rosin-modified resin.

[Urethane resin with acidic group]
The urethane resin having an acidic group is not particularly limited, and examples thereof include a urethane resin obtained by reacting a polyol and a polyisocyanate having an acidic group, and a urethane resin obtained by reacting a polyol and a polyisocyanate with an acid-modified hydroxyl group. and resins obtained by acid-modifying the amino groups in a urethane urea resin obtained by reacting a polyamine with an isocyanate group in a urethane resin obtained by reacting a polyol with a polyisocyanate.
Further, as the urethane resin having an acidic group, a resin obtained by reacting a polyol containing a hydroxy acid and a polyisocyanate may be used. By using a hydroxy acid as a polyol, an acid value derived from a carboxy group can be imparted to the urethane resin, and the removability can be improved. Further, when the urethane resin having an acidic group has an isocyanate group, a portion of the isocyanate group may be reacted with a polyamine to introduce a urea bond to form a urethane urea.

《Polyol》
Polyol is a general term for compounds having at least two hydroxyl groups in one molecule. The number average molecular weight of the polyol is preferably 500 to 10,000, more preferably 1,000 to 5,000. The above-mentioned number average molecular weight is calculated from the hydroxyl value of the polyol, and the hydroxyl value refers to a value measured according to JIS K 0070. When the number average molecular weight of the polyol is 500 or more, the primer layer has excellent flexibility and improves adhesion to the plastic substrate. When the number average molecular weight is 10,000 or less, blocking resistance against plastic substrates is excellent.

The polyol is not particularly limited, and at least one polyol selected from the group consisting of polyester polyols, polyether polyols, and polycarbonate polyols is more preferably used. Furthermore, the polyol may also contain other dimer diols, hydrogenated dimer diols, castor oil-modified polyols, and the like.
That is, the urethane resin preferably contains a structural unit derived from at least one polyol selected from the group consisting of polyester polyols, polyether polyols, and polycarbonate polyols. More preferably, the polyester polyol contains a structural unit derived from the polyester polyol, since the removability is improved by alkaline hydrolysis of the ester bond site of the polyester polyol.
The content of the structural unit derived from the polyol is preferably 10 to 75% by mass, more preferably 15 to 70% by mass, and still more preferably 20 to 65% by mass, based on the total amount of the urethane resin. The content of the structural units derived from the polyester polyol is preferably 5% by mass or more, more preferably 30% by mass or more, even more preferably 60% by mass or more, particularly preferably 80% by mass, based on the total amount of the polyester polyol-derived structural units. That's all.

《Hydroxy acid》
The polyol may also contain a hydroxy acid. The above-mentioned hydroxy acid refers to a compound having both a hydroxyl group, which is an active hydrogen group, and an acidic functional group in one molecule. The acidic functional group refers to a functional group that can be neutralized with potassium hydroxide when measuring an acid value, and specifically includes a carboxy group and a sulfonic acid group, with a carboxy group being preferred. As such a hydroxy acid, for example, dimethylolalkanoic acids such as 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, and 2,2-dimethylolvaleric acid are preferably used.

《Polyisocyanate》
The above polyisocyanate is not particularly limited and can be selected from conventionally known polyisocyanates. Preferably, the diisocyanate or triisocyanate is included, and more preferably an aromatic, aliphatic or alicyclic diisocyanate is included. These may be used alone or in combination of two or more.

《Polyamine》
The polyamine used to form the urethane urea is not particularly limited, and is preferably a diamine compound. Further, a diamine having a hydroxyl group may be used since it can introduce a hydroxyl group into the urethane resin.

The acid value of the urethane resin having acidic groups is preferably 15 mgKOH/g or more, more preferably 15 to 70 mgKOH/g, and still more preferably 20 to 50 mgKOH/g. It is preferable that the content is 15 mgKOH/g or more because the releasability with the desorption liquid becomes good, and it is preferable that the content is 70 mgKOH/g or less because the adhesion to the substrate and the retort resistance are good. The hydroxyl value of the urethane resin is preferably 1 to 35 mgKOH/g, more preferably 10 to 30 mgKOH/g. If it is 1 mgKOH/g or more, the releasability by the desorbing liquid will be good, so it is preferable, and if it is 35 mgKOH/g or less, the adhesion to the substrate will be good, so it is preferable.

The weight average molecular weight of the urethane resin having acidic groups is preferably 10,000 to 100,000, more preferably 15,000 to 70,000, even more preferably 15,000 to 50,000. The molecular weight distribution (Mw/Mn) of the urethane resin is preferably 6 or less. Mw represents weight average molecular weight, and Mn represents number average molecular weight. When the molecular weight distribution is 6 or less, the releasability, drying properties of the primer composition, and retort resistance are excellent. Furthermore, the smaller the molecular weight distribution, that is, the sharper the molecular weight distribution, the more uniformly the dissolution and peeling action by the desorbing liquid occurs, and the releasability of the plastic base material improves. The molecular weight distribution is more preferably 5 or less, still more preferably 4 or less. Further, the molecular weight distribution is preferably 1.5 or more, more preferably 1.2 or more.
In this specification, Mw, Mn, and molecular weight distribution (Mw/Mn) are polystyrene equivalent values determined by gel permeation chromatography (GPC).

The urethane resin having an acidic group may have an amine value. When the urethane resin has an amine value, the amine value is preferably 0.1 to 20 mgKOH/g, more preferably 1 to 10 mgKOH/g. Within the above range, the adhesion to the substrate is excellent.

The number of urethane bonds in the polyurethane resin having acidic groups is preferably 1 to 3 mmol/g, more preferably 1.5 to 2 mmol/g. Further, the number of urea bonds is preferably 0 to 3 mmol/g, more preferably 0.2 to 1 mmol/g. Further, the total number of urethane bonds and the number of urea bonds is preferably 1 to 6 mmol/g, more preferably 1.7 to 3 mmol/g.
By setting the number of urethane bonds and the number of urea bonds within the appropriate ranges, the releasability and substrate adhesion are improved.

[Acrylic resin with acidic group]
Examples of acrylic resins having acidic groups include polymers obtained by polymerizing monomers containing (meth)acrylic monomers having acidic groups such as (meth)acrylic acid and maleic acid; (meth)acrylic monomers having hydroxyl groups and glycidyl groups; After polymerizing a monomer containing a monomer, the functional group is modified to introduce a carboxy group (for example, a maleic anhydride-modified resin).
The acid value of the acrylic resin having an acidic group is preferably 50 mgKOH/g or more, more preferably 100 mgKOH/g or more.

[Rosin modified resin]
Rosin modified resin is a resin prepared using rosin as one of the raw materials. Rosin contains a mixture of resin acids such as abietic acid, palustric acid, isopimaric acid, and levopimaric acid, and these resin acids contain hydrophilic and chemically active carboxy groups, and some contain conjugated double bonds. There are things to prepare for. Therefore, polyhydric alcohols and polybasic acids are combined to perform condensation polymerization, resol, which is a condensate of phenol, is added to the benzene ring contained in the rosin skeleton, and dienophilic maleic anhydride or maleic acid is reacted with Diels-Alder reaction. Various rosin-modified resins have been prepared by adding a maleic acid or maleic anhydride skeleton to the rosin. Various kinds of such rosin modified resins are commercially available, and it is also possible to obtain and use them.

Examples of the rosin-modified resin include maleated rosin, fumarized rosin, rosin-modified maleic acid resin, rosin-modified fumaric acid resin, rosin-modified phenolic resin, rosin-modified alkyd resin, and rosin-modified polyester resin. In the present invention, any rosin-modified resin may be used, but among these, at least one selected from the group consisting of maleic acid, maleic anhydride, fumaric acid, and fumaric anhydride is derived from the structure thereof. It is preferable to use a compound containing a portion as follows. A resin that “contains in its structure at least one moiety selected from the group consisting of maleic acid, maleic anhydride, fumaric acid, and fumaric anhydride” refers to a resin that contains maleic acid, maleic anhydride, It is prepared using at least one selected from the group consisting of acid, fumaric acid, and fumaric anhydride, such as rosin-modified maleic acid obtained by condensation polymerization of maleic acid or fumaric acid as part of a polybasic acid. Acid resins, rosin-modified fumaric acid resins, maleated rosins and fumarated rosins with structures in which maleic acid, maleic anhydride, fumaric acid, and fumaric anhydride are added as dienophiles through Diels-Alder reactions, and the functionalities contained in these. It means a resin etc. in which other chemical species are polymerized using the group.

The acid value of the rosin modified resin is preferably 10 to 400 mgKOH/g, more preferably 100 to 300 mgKOH/g.

(Other ingredients)
The primer layer may contain a resin other than a water-soluble resin or a compound having an acidic group.
Examples of such resins include cellulose resins, polyamide resins, vinyl chloride resins such as vinyl chloride-vinyl acetate copolymer resins and vinyl chloride-acrylic copolymer resins, ethylene-vinyl acetate copolymer resins, and vinyl acetate resins. , acrylic resin, styrene resin, dammar resin, styrene-acrylic copolymer resin, polyester resin, alkyd resin, terpene resin, phenol-modified terpene resin, ketone resin, cyclized rubber, chloride rubber, butyral, polyacetal resin, petroleum resin, and These modified resins can be mentioned. These resins may be used alone or in combination of two or more.
Among these, the primer layer preferably contains at least one resin selected from the group consisting of cellulose resin, vinyl chloride resin, rosin resin, and acrylic resin. More preferably, vinyl chloride resin or acrylic resin is included.
The mass ratio of the urethane resin having acidic groups to other resins (urethane resin having acidic groups: other resins) is preferably 95:5 to 50:50. If it is within the above range, when the printed layer is peeled off together with the primer layer in a basic aqueous solution, the printed layer will be peeled off in a thin film state and recovery will be easy, which is preferable.

The primer layer may contain an extender pigment. Examples of extender pigments include metal oxides such as silica, barium sulfate, kaolin, clay, calcium carbonate, magnesium carbonate, zinc oxide, and zirconium oxide. Among these, silica is preferred, and hydrophilic silica is more preferred.
The average particle diameter of the extender pigment is preferably 0.5 to 10 μm, more preferably 1 to 8 μm. The content of the extender pigment in the primer layer is preferably 0.5 to 10% by mass, more preferably 1 to 5% by mass. When the average particle diameter and the extender pigment content are within the above ranges, the wettability of the printing layer is improved and the image quality is improved.

The primer layer may be a layer in which the above-mentioned urethane resin having acidic groups is crosslinked with a curing agent. By introducing a crosslinked structure into the primer layer, penetration and bleeding of the printed layer formed on the primer layer are suppressed, and excellent image quality can be exhibited.
Examples of the curing agent include polyisocyanate. The polyisocyanate is not particularly limited and can be selected from conventionally known polyisocyanates, such as aliphatic polyisocyanates and araliphatic polyisocyanates. These may be used alone or in combination of two or more.

The primer layer may further contain known additives. Known additives include, for example, dispersants, wetting agents, adhesion aids, leveling agents, antifoaming agents, antistatic agents, viscosity modifiers, metal chelates, trapping agents, antiblocking agents, wax components other than those listed above, Examples include silane coupling agents.

The thickness of the primer layer is preferably in the range of 0.5 to 3.0 μm, more preferably 0.6 to 2.0 μm, even more preferably 0.8 to 1.5 μm, and is formed using a known method. be able to.

[Adhesive layer]
The laminate of the present invention may have an adhesive layer, and when the laminate has an adhesive layer, the adhesive layer is disposed in contact with the plastic base material and contains a compound having an acidic group, It is preferable to play the role of detaching the plastic base material by dissolving, peeling, etc. with a detaching liquid. When the adhesive layer contains a resin having an acidic group or a low molecular weight compound having an acidic group, the adhesive layer can be removed using the above-mentioned basic aqueous solution.
For the above-mentioned compound having an acidic group, resin having an acidic group, and low molecular weight compound having an acidic group, the description of (compound having an acidic group) in the above-mentioned [Primer layer] section can be referred to.
Further, the method of forming the adhesive layer is not limited, and it can be formed using a known method.

From the viewpoint of removability, the adhesive layer is a cured adhesive containing a polyester polyol having an acidic group and at least one polyisocyanate selected from the group consisting of aliphatic polyisocyanates and araliphatic polyisocyanates. It may be. The cured product corresponds to a resin having an acidic group.
Further, the adhesive layer is a cured product of an adhesive containing a polyester polyol, at least one polyisocyanate selected from the group consisting of aliphatic polyisocyanates and araliphatic polyisocyanates, and a low molecular compound having an acidic group. It may be.

<Plastic base material layer>
Examples of the plastic base material include polyolefin resin, polyester resin, polyamide resin, polystyrene resin, vinyl chloride resin, vinyl acetate resin, ABS resin, acrylic resin, acetal resin, polycarbonate resin, polyvinyl alcohol resin, and cellulose plastic. It will be done.

From the viewpoint of reuse as a recycled base material, the plastic base material is preferably a polyolefin base material containing a polyolefin resin. Base materials containing such polyolefin resins include, for example, plastic base materials such as polyethylene (PE) and biaxially oriented polypropylene (OPP), as well as low density polyethylene (LDPE) and linear low density polyethylene (LLDPE). ), high-density polyethylene (HDPE), acid-modified polyethylene, unoriented polypropylene (CPP), acid-modified polypropylene, and copolymerized polypropylene.

The thickness of the plastic base layer is not particularly limited, and may be appropriately selected depending on the application. Preferably it is 5 to 200 μm, more preferably 10 to 150 μm. Further, examples of the gas barrier base material include aluminum foil, a vapor-deposited layer of metal such as aluminum, and a vapor-deposited layer of metal oxide such as silica and alumina. The thickness of aluminum foil is often used in the range of 3 to 50 μm from an economical point of view. Moreover, since the aluminum foil, the aluminum vapor deposited layer, and the alumina vapor deposited layer are dissolved in a basic aqueous solution and desorbed, they function as a desorption layer and can separate adjacent polyolefin resins.

An example of the structure of the laminate of the present invention is shown below, but the structure is not limited thereto. Moreover, in the following configuration, the "base material layer" does not need to be a single layer, and may be a laminate in which a plurality of base materials are laminated.
・Plastic base material layer / Printing layer ・Plastic base material layer / Primer layer / Printing layer ・Plastic base material layer / Printing layer / Adhesive layer / Plastic base material layer ・Plastic base material layer / Primer layer / Printing layer / Adhesive Layer / Plastic base material layer / Base material layer / Printing layer / Adhesive layer / Plastic base material layer / Plastic base material layer / Primer layer / Printing layer / Adhesive layer / Vapor deposition layer / Plastic base material layer

<Method for producing molding material>
A molding material can be manufactured by melt-kneading the plastic base material recovered by the separation and recovery method described above. The method for producing a molding material of the present invention preferably includes the following steps 1 to 3. When the molding material contains a masterbatch, it may further include the following step 4.
(Step 1) A step of crushing the above-mentioned laminate and immersing it in a desorption liquid to remove the plastic base material from the laminate (Step 2) A step of washing the plastic base material obtained in Step 1 with water ( Step 3) Melting and kneading the plastic base material obtained in Step 2 to obtain recycled resin (Step 4) Mixing a masterbatch into the recycled resin obtained in Step 3

The method for crushing the packaging material in Step 1 is not particularly limited, and examples include methods using a jaw crusher, impact crusher, cutter mill, stamp mill, ring mill, roller mill, jet mill, and hammer mill.
Step 2 may further include a drying step as necessary. Through step 2, a recycled base material (also referred to as recycled plastic base material) can be obtained.

In the melting and kneading step in step 3, various additives are added as necessary, and the mixture is mixed using a Henschel mixer, tumbler, disper, etc., followed by a kneader, roll mill, super mixer, Henschel mixer, Shugi mixer, vertical granulator, high Using speed mixers, fur matrix, ball mills, steel mills, sand mills, vibration mills, attritors, batch-type kneaders such as Banbury mixers, twin-screw extruders, single-screw extruders, rotor-type twin-screw kneaders, etc. Refers to mixing or dispersing. As a result, recycled resin, which is a resin composition, is obtained. The shape of the recycled resin is not particularly limited, and may be in the form of pellets, powder, granules, or beads. It is preferable to use a twin-screw extruder in the melt-kneading step.

[Master Badge]
The molding material of the present invention can further contain a masterbatch. The masterbatch is not particularly limited as long as it is compatible with the recycled resin, and generally, a mixture of a thermoplastic resin such as polyethylene resin or polypropylene resin and a colorant can be used. The thermoplastic resins contained in the masterbatch may be used alone or in combination of two or more.
The masterbatch in the present invention includes alkali metal, alkaline earth metal, or zinc metal soap, hydrotalcite, nonionic surfactant, cationic surfactant, anionic surfactant, within a range that does not impede the effects of the present invention. It may also contain additives, amphoteric surfactants, antistatic agents, flame retardants such as halogen-based, phosphorus-based or metal oxides, lubricants such as ethylene bisalkylamides, antioxidants, ultraviolet absorbers, and fillers.

<Molded object>
A molded body can be obtained by heat-molding the molding material obtained by the above-described manufacturing method. The heat molding method is not particularly limited, and examples thereof include injection molding, extrusion molding, blow molding, and compression molding.
The molding material manufactured using the plastic base material recovered by the separation and recovery method of the present invention has a high quality because the printed layer is detached and re-deposition of the detached components is suppressed, and it is suitable for home appliances. It can be used in a variety of fields, including products, stationery, automobile parts, toys and sporting goods, medical use, and building and construction materials.

EXAMPLES Hereinafter, the present invention will be explained in detail with reference to Examples, but the present invention is not limited to these Examples. Note that parts and % in the present invention represent parts by mass and % by mass unless otherwise noted.

<Molecular weight and molecular weight distribution>
The weight average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (Mw/Mn) were measured by GPC (gel permeation chromatography) and determined as a converted molecular weight using polystyrene as a standard substance. The measurement conditions are shown below.
GPC device: Showa Denko Shodex GPC-104
Column: The following columns were connected in series and used.
Showa Denko Shodex LF-404 2 pieces Showa Denko Shodex LF-G
Detector: RI (differential refractometer)
Measurement conditions: Column temperature 40℃
Eluent: Tetrahydrofuran Flow rate: 0.3 mL/min

<Acid value, hydroxyl value>
Acid value and hydroxyl value were measured according to the method described in JIS K 0070 (1992).

<Production of primer composition and resin for printing ink>
[Synthesis Example 1-1] (Polyurethane resin P1)
PPA (consisting of a polycondensate of propylene glycol and adipic acid, number average molecular weight 2, 000 polyester polyol) 152.2 parts, PPG (polyether polyol consisting of polypropylene glycol and having a number average molecular weight of 2,000) 15.2 parts, BD (1,4-butanediol) 13.6 parts, IPDI (isophorone) 99.8 parts of diisocyanate) and 200 parts of NPAC (n-propyl acetate) were charged and reacted at 90°C for 5 hours to obtain a urethane prepolymer solution having isocyanate groups at the ends.
Next, a mixture of 19.2 parts of AEA (2-(2-aminoethylamino)ethanol) and 350 parts of IPA (isopropyl alcohol) was added dropwise at room temperature over 60 minutes, and then reacted at 70°C for 3 hours. A polyurethane resin solution was obtained.
NPAC was added to the obtained polyurethane resin solution to adjust the solid content, and a polyurethane resin P1 with a solid content concentration of 30%, a weight average molecular weight of 27,000, Mw/Mn = 3.1, and an acid value of 0.0 mgKOH/g was obtained. A solution of was obtained.

[Synthesis Example 1-2] (Polyurethane resin P2)
135.7 parts of PPA, 13.6 parts of PPG, DMPA (2,2 -dimethylolpropanoic acid), 105.7 parts of IPDI, and 200 parts of NPAC were charged and reacted at 90°C for 5 hours to obtain a urethane prepolymer solution having isocyanate groups at the terminals.
Next, a mixture of 16.7 parts of AEA and 350 parts of IPA was added dropwise at room temperature over 60 minutes, and then reacted at 70°C for 3 hours to obtain a polyurethane resin solution.
NPAC was added to the obtained polyurethane resin solution to adjust the solid content, resulting in a polyurethane resin P2 having a solid content concentration of 30%, a weight average molecular weight of 30,000, Mw/Mn=3.0, and an acid value of 39.3 mgKOH/g. A solution of was obtained.

<Manufacture of primer layer forming composition>
[Production Example 1-1] (Primer composition S1)
87 parts of polyurethane resin P2 solution, 5 parts of EA, 5 parts of IPA, and 3 parts of silica particles (manufactured by Mizusawa Chemical Co., Ltd. P-73: hydrophilic silica particles with an average particle size of 3.8 μm) were stirred and mixed using a disper, and the primer was A composition S1 was obtained.

<Manufacture of printing ink>
[Manufacturing example 2-1] (Printing ink R1)
Indigo pigment P. B. 10 parts of C.I. Pigment Blue 15, 25 parts of polyurethane resin P1 solution, PVC solution (vinyl chloride-vinyl acetate copolymer resin solution (Solvine TAO manufactured by Nissin Chemical, solid content 30%, EA solution) ), 10 parts of EA, and 10 parts of IPA were mixed and stirred, and a dispersion treatment was performed for 20 minutes using a sand mill as a bead mill. Thereafter, 20 parts of polyurethane resin P1 solution, 10 parts of EA, and 10 parts of IPA were mixed and stirred to obtain printing ink R1. Table 1 shows the total amount of blending during dispersion and post-blending.

[Manufacturing examples 2-2 to 6] (Printing ink R2 to 6)
Printing inks R2 to R6 were obtained in the same manner as in Ink Production Example 2-1, except that the raw materials and blending ratios shown in Table 1 were used. The blending amounts in Table 1 are the total of the blending at the time of dispersion and the post-blending. The blending amount at the time of dispersion was adjusted so that the resin solution at the time of post-blending was 20 parts.

Abbreviations in Table 1 are shown below.
P. B. 15:C. I. Pigment Blue 15
SYNERGIST 2100: Pigment derivative, BYK-SYNERGIST 2100 manufactured by BYK-CHEMY JAPAN
BYK-142: Resin type dispersant, manufactured by BYK Chemie Japan DISPERBYK-142
PVC solution: Vinyl chloride-vinyl acetate copolymer resin solution, Nissin Chemical Solvain TAO (solid content 30%, EA solution)
EA: Ethyl acetate IPA: Isopropyl alcohol

<Manufacture of polyol used in adhesives>
[Synthesis Example 2-1] (Polyester polyol B1)
124 parts of ethylene glycol, 212 parts of neopentyl glycol, 368 parts of 1,6-hexanediol, 645 parts of isophthalic acid, and adipine were placed in a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping tank, and a nitrogen gas introduction tube. 36 parts of acid and 265 parts of sebacic acid were charged, and the temperature was raised to 250° C. with stirring under a nitrogen stream to perform an esterification reaction. After the reaction was continued until a predetermined amount of water was distilled out and the acid value became 5 or less, the pressure was gradually reduced and the deglycol reaction was performed at 1 mmHg or less for 5 hours to obtain a polyester polyol. Thereafter, 35 parts of isophorone diisocyanate was gradually added, and the reaction was carried out at 150° C. for about 2 hours to obtain a polyester polyurethane polyol. 12.0 parts of ethylene glycol bisanhydrotrimellitate was added to 100 parts of this polyester polyurethane polyol, reacted at 180°C for about 2 hours, and then diluted with ethyl acetate until the solid content concentration was 50%. A solution of partially acid-modified polyester polyol B1 having an average molecular weight of 9,000 and an acid value of 30.3 mgKOH/g was obtained.

[Synthesis Example 2-2] (Polyester polyol B2)
58 parts of ethylene glycol, 412 parts of diethylene glycol, 343 parts of neopentyl glycol, 517 parts of isophthalic acid, and 393 parts of adipic acid were placed in a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping tank, and a nitrogen gas introduction pipe. The temperature was raised to 250° C. while stirring under a nitrogen stream to carry out an esterification reaction. After the reaction was continued until a predetermined amount of water was distilled out and the acid value became 5 or less, the pressure was gradually reduced and the deglycol reaction was performed at 1 mmHg or less for 5 hours to obtain a polyester polyol. 4.0 parts of trimellitic anhydride was added to 100 parts of this polyester polyol, reacted at 180°C for about 2 hours, and then diluted with ethyl acetate until the solid content concentration was 50%, resulting in a number average molecular weight of 2,000. A solution of partially acid-modified polyester polyol B2 having an acid value of 23.5 mgKOH/g was obtained.

<Adjustment of polyisocyanate>
[Preparation Example 1] (Polyisocyanate C1)
Coronate 2785 (biuret type polyisocyanate derived from hexamethylene diisocyanate, manufactured by Tosoh Corporation) was diluted with ethyl acetate to adjust the solid content concentration to 50% and NCO% = 9.6%, and a solution of polyisocyanate C1 was prepared. Obtained.

<Manufacture of adhesive>
[Production Example 3-1] (Adhesive D1)
90 parts of polyester polyol B1 solution, 10 parts of polyester polyol B2 solution, and 8 parts of polyisocyanate C1 solution were blended, and EA was added to prepare an adhesive solution with a solid content concentration of 30%.

<Manufacture of laminate>
The method for manufacturing the laminate will be described below. The primer composition and printing ink were each made using a mixed solvent of EA/IPA (mass ratio 70/30) so that the viscosity was 15 seconds (25°C, Zahn cup #3 (manufactured by Rigosha)). It was used after diluting it. Further, the thicknesses of the primer layer and the printing layer were each adjusted to about 1.5 μm.

[Manufacturing Example 4-1] (Laminated body L1)
The diluted primer composition S1 and printing ink R1 were printed on OPP (corona-treated stretched polypropylene film, thickness 20 μm) in this order using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm, and the mixture was heated at 50° C. It was dried to obtain a laminate having a configuration of OPP/S1/R1.
Next, adhesive D1 was applied onto the printed layer of the obtained laminate using a dry laminating machine so that the film thickness after drying became approximately 3 μm, and after drying, CPP (unstretched polypropylene film, thickness 50 μm) was applied. By laminating them together, a laminate L1 having a structure of base material layer (OPP)/primer layer (S1)/printing layer (R1)/adhesive layer (D1)/base material layer (CPP) was obtained.

[Production Examples 4-2 to 4-5] (Laminated bodies L2 to 5)
Laminated bodies L2 to L5 were obtained in the same manner as in Production Example 4-1, except that the printing ink was changed to those listed in Table 2.

[Manufacturing Example 4-6] (Laminated body L6)
The diluted primer composition S1 and printing ink R3 were printed on OPP in this order using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm, and dried at 50° C. to form a base layer (OPP). A laminate L6 having a configuration of /primer layer (S1)/printing layer (R3) was obtained.

[Manufacturing Example 4-7] (Laminated body L7)
The diluted printing ink R3 was printed on OPP using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm, and dried at 50°C to form the base layer (OPP)/printing layer (R3). A laminate L7 was obtained.

[Manufacturing Example 4-8] (Laminated body L8)
A laminate L8 was obtained in the same manner as in Production Example 4-7, except that the printing ink was changed to those listed in Table 2.

The abbreviations in Table 2 are shown below.
OPP: Corona treated stretched polypropylene film, thickness 20μm
CPP: unstretched polypropylene film, thickness 50 μm

<Production of desorption liquid>
[Production Example 5-1] (Detachment liquid A1)
2 parts of sodium hydroxide and 98 parts of water were blended and stirred with a disper to obtain a desorbed liquid A1.

[Production Examples 5-2 to 4] (Detachment liquid A2 to 4)
In addition to sodium hydroxide and water, POE stearyl ether (POE addition number: 12, HLB: 13.9) is used as a surfactant, BYK-1650 (manufactured by BYK Chemie Japan, silicone emulsion type antifoaming agent, Desorption liquids A2 to A4 were obtained in the same manner as in Production Example 5-1, except that the solid content (solid content concentration 27.5%) was blended as shown in Table 3.

<Separation and recovery of laminate>
[Example 1]
In a 1000 mL stainless steel beaker, 500 g of the desorption liquid A3 and 20 g of a sample cut out from the laminate L4 into a size of 1 cm x 1 cm were placed, and the mixture was stirred at 70° C. and 2000 rpm. The following evaluation was performed regarding the state of separation and recovery of the laminate.

[Examples 2 to 13, Comparative Examples 1 to 4]
In addition, the separation and recovery state of the laminate was evaluated using the same method as in Example 1, except that the materials, the amounts of the laminate and printed layer relative to the desorption liquid, and the stirring speed were changed to those listed in Table 4. went. Note that 0.2 g of the laminate of Comparative Example 4 corresponds to 100 samples obtained by cutting the laminate L4 into a size of 1 cm x 1 cm.
The results are shown in Table 4. Regarding the amounts of the laminate, printed layer, and film relative to the desorption liquid, the density of the primer layer, printed layer, and adhesive layer is 1 g/cm ³ , and the density of the OPP base material and CPP base material is 0.91 g/cm 3 . It was calculated as ³ .

<Evaluation of laminate>

(removability)
At 15 minutes, 30 minutes, and 1 hour after the start of stirring, the base materials were sampled, washed with water, and dried. Ten OPP substrates were sampled from the obtained substrates, and the removal rate of the printed layer was visually confirmed and evaluated based on the following criteria.
A (Excellent): 90% or more of the printed layer has peeled off from the base material 15 minutes after the start of stirring.
B (Good): 90% or more of the printed layer has peeled off on the base material 30 minutes after the start of stirring.
C (Acceptable): 90% or more of the printed layer has peeled off from the base material 1 hour after the start of stirring.
D (unacceptable): 90% or more of the printed layer has not peeled off on the base material 1 hour after the start of stirring.

(Reattachability)
Two hours after the start of stirring, the detached base material was collected in a colander with openings of 1 mm, washed with water, and dried. Ten OPP substrates were sampled from the obtained substrates, and the 10 substrates were stacked and the color values L ^* _x , a ^* _x , b were measured using a spectrophotometer (manufactured by X-rite, X-rite eXact). ^* _x was measured.
Similarly, for the OPP base material before printing, OPP (20 g) cut into a size of 1 cm x 1 cm was soaked in desorption liquid A3 (500 g), stirred at 70 ° C. and 2000 rpm for 2 hours, washed with water, and dried. , 10 substrates were sampled, and the color values L ^* _y , a ^* _y , and b ^* _y were measured by stacking the 10 substrates.
The color difference ΔE was determined using the following calculation formula, and the reattachability was evaluated based on the following criteria.
(Formula) ΔE = ((L ^* _x - L ^* _y ) ² + (a ^* _x - a ^* _y ) ² + (b ^* _x - b ^* _y ) ² ) ^1/2
A (Excellent): ΔE is less than 3 B (Good): ΔE is 3 or more and less than 10 C (Acceptable): ΔE is 10 or more and less than 20 D (Poor): Other than A to C

(Particle size of detached printing layer components)
After stirring for 2 hours from the start of stirring, the detached base material was removed using a colander with openings of 1 mm, and a detached liquid in which the detached printed layer components were dispersed was recovered. The particle size distribution of the desorbed liquid was measured using a laser diffraction/scattering particle size distribution analyzer (Microtrac MT-3000EX (II) manufactured by Microtrac Bell Co., Ltd.). A 2% aqueous sodium hydroxide solution was used as a dispersion medium. From the obtained volume frequency particle size distribution curve, determine the 10 volume % diameter (D10), median diameter (50 volume % diameter, D50), and 90 volume % diameter (D90), and calculate the span value of the particle size distribution from the obtained values. A ((D90-D10)/D50) was determined.

(processing efficiency)
Two hours after the start of stirring, the OPP base material and CPP base material that had been desorbed were collected, washed with water, dried, and then the weight of the collected base material was measured, the amount relative to the charged desorption liquid was determined, and the evaluation was made using the following criteria. did.
A (Excellent): Amount of recovered base material relative to the charged desorbed liquid is 3% or more B (Good): Amount of recovered base material relative to the prepared desorbed liquid is 1% or more and less than 3% C (Acceptable): Recovery relative to the prepared desorbed liquid Amount of base material is 0.1% or more and less than 1% D (unavailable): Amount of recovered base material is less than 0.1% with respect to the charged and desorbed liquid

(Production of recycled film and evaluation of transmittance)
Two hours after the start of stirring, the desorbed OPP base material and CPP base material are collected, washed with water, dried, and then the collected base material is extruded at 200°C using a single-screw extruder, and through a pelletizing process, the recycled resin is Obtained pellets. The recycled resin was extruded at 200° C. using a T-die film molding machine to produce a recycled film with a thickness of 50 μm.
The haze of the recycled film was measured using a haze meter (manufactured by JEOL Ltd., SH7000) and evaluated based on the following criteria.
A (Excellent): Haze is 20% or less B (Good): Haze is 20% or more and less than 40% C (Acceptable): Haze is 40% or more and less than 60% D (Poor): Haze is 60% or more

From the above evaluation results, the separation and recovery method of the present invention can easily remove the printed layer from the laminate even when the amount of laminate processed is large, and can produce high-quality printed layers with less redeposition. It was shown that a recycled base material could be obtained, and furthermore, a high-quality molding material with little coloring could be obtained.

Claims (11)

A laminate including at least a plastic base material layer and a printed layer is immersed in a desorption liquid, and the printed layer is removed so that the volume-based median diameter (D50) of the printed layer components desorbed from the plastic base layer is 1 μm or more. A method for separating and recovering a laminate, the method comprising the steps of separating and recovering a plastic base material,
A method for separating and recovering a laminate, wherein the printed layer accounts for 0.01% by mass or more based on the total mass of the desorbed liquid. 2. The method for separating and recovering a laminate according to claim 1, wherein the desorbed printed layer component has a span value A expressed by the following formula of 10 or less.
A=(D90-D10)/D50
D10: Cumulative 10% diameter of the volume-based particle size distribution obtained by laser diffraction particle size distribution measurement of the detached printed layer components D90: Cumulative 10% diameter of the volume-based particle size distribution obtained by laser diffraction particle size distribution measurement of the detached printed layer components Cumulative 90% diameter The method for separating and recovering a laminate according to claim 1 or 2, wherein the plastic base material layer is a polyolefin base material. The laminate according to claim 1 or 2, wherein the desorption liquid contains water and a surfactant, and the content of the surfactant is 0.001% by mass or more based on the total mass of the desorption liquid. Separation and recovery method. 3. The printing layer according to claim 1 or 2, wherein the printing layer contains a colorant, a binder resin, and a dispersant, and the content of the dispersant is 0.01% by mass or more based on the total mass of the colorant. Separation and recovery method for laminates. The method for separating and recovering a laminate according to claim 5, wherein the dispersant includes a pigment derivative and/or a resin-type dispersant. The method for separating and recovering a laminate according to claim 6, wherein the dispersant contains a pigment derivative, and the content of the pigment derivative is 0.01 to 10% by mass based on the total mass of the colorant. The method for separating and recovering a laminate according to claim 1 or 2, wherein the laminate contains 1.5% by mass or more based on the total mass of the desorbed liquid. 3. The method for separating and recovering a laminate according to claim 1, wherein the desorption liquid is a basic aqueous solution, and the method includes a step of desorbing the printed layer in the basic aqueous solution and recovering the plastic base material. A method for producing a molding material, comprising melting and kneading a plastic base material recovered by the method for separating and recovering a laminate according to claim 1 or 2. A method for producing a molded article, comprising heating and molding a molding material obtained by the method according to claim 10.